High incidence of neurologic complications following rapid correction of severe hyponatremia in polydipsic patients.

BACKGROUND

Patients with self-induced water intoxication usually tolerate a large, rapid increase in plasma sodium without developing osmotically induced central pontine myelinolysis. However, we have previously reported a case of clinically suspected pontine myelinolysis in a patient with self-induced water intoxication. The purpose of our study was to investigate if a subgroup of these patients may also be vulnerable to neurologic complications of hyponatremia therapy.

METHOD

Over a 10-year period, we identified retrospectively 12 polydipsic patients having a total of 24 episodes of symptomatic hyponatremia with plasma sodium < or = 115 mmol/L. The mode of treatment, the kinetics of correction, and the neurologic outcome were recorded. The presence of alcoholism was noted.

RESULTS

Seven patients recovered uneventfully from 19 episodes of symptomatic hyponatremia. Five patients had delayed neurologic complications. Late therapy and/or respiratory arrest might have been associated with the complications for 2 patients. The other 3 patients experienced clinical features of central pontine myelinolysis leading to death in 1. Patients with neurologic complications had a higher maximal 24-hour increase in plasma sodium concentration (21.8 +/- 3.9 vs. 15.5 +/- 5.1 mmol/L, p < .02), and a higher incidence of both overcorrection to hypernatremia and chronic alcoholism, often associated with poor nutrition. All 5 patients became water intoxicated at home, and 2 patients with pontine dysfunction had subacute rather than acute hyponatremia.

CONCLUSION

A large rapid increase in plasma sodium may also be detrimental in patients with self-induced water intoxication when they are alcoholic, malnourished, and have nonacute hyponatremia.